On Tue, Oct 7, 2008 at 10:53 AM, Richard Fairhurst <[EMAIL PROTECTED]> wrote: > But I do wonder a little (particularly with reference to Martin's observation > about 70-footers > on the T&M) whether some of this might have been exacerbated by 20 years of > BW buggering > around with paddles. The T&M locks have been in operation for 240-ish years - > surely it > didn't survive all that time with locks that were unsuitable for the main > length of boat that > used them?
I'm not sure many locks or paddles have been changed since original construction (apart from reductions, or grills), but what has changed is the operating method. Most locks were designed to bring a moving boat to a stop when the ground paddle is first raised, thus stopping it from crashing into the cill. By the time the boat has stopped with a well timed paddle rise the water flows then hold it on the top gate. I did this with Shoestring up the Alyesbury Arm and didn't have any problems with the boat moving backwards (but did involve some carefull timing). Cheers, Mike -- Michael Askin http://shoestring_DOT_zapto_DOT_org/
